ENGINEERING TECHNOLOGY

Scientists have made progress in the self-luminescence of fluoride glass


Recently, Chen Danping’s team, a researcher at the High Power Laser Unit Technology Laboratory of the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, discovered the orange-red self-luminescence phenomenon of BaF2-B2O3 glass. The findings were published in the Journal of Non-Crystalline Solids.

The strong and sharp electron transition within the 4F shell of rare earth ions makes it often used to prepare laser materials and phosphors. Rare-earth-doped LED materials face two problems. First, due to the low transparency of phosphor coating and large light scattering, the luminous efficiency of LED is reduced; The second is the non-renewability of rare earth materials and environmental pollution. The development of environmentally friendly rare earth-free high-efficiency fluorescent LED materials has become the future research direction.

It was found that the transparent BaF2-B2O3 glass system without rare earth ions prepared under CO reduction atmosphere exhibited orange-red self-luminescence under near-ultraviolet light, and produced 550~850 nm broadband luminescence centered on 650 nm under broadband light excitation of about 397 nm.

In order to explore the mechanism of the autoluminescence phenomenon, the researchers conducted comparative experiments under the reducing atmosphere and the air atmosphere. At the same time, based on the results of fluorescence spectroscopy, electron spin resonance, Raman and X-ray photoelectron spectroscopy, it is inferred that the reduction atmosphere leads to the reduction of B3+ to B2+ in glass, and fluorescence emission caused by the s→p transition of B2+. This study proposes the luminescence phenomenon of B2+, which provides a new idea for the study of glass luminescence phenomenon. The orange self-luminous glass material developed in this study has the characteristics of no rare earth ion doping, high transparency, low raw material cost, simple preparation process, and wide fluorescence emission band, and has potential application prospects in new orange LED glass. (Source: Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences)

Related paper information:https://doi.org/10.1016/j.jnoncrysol.2023.122512

Figure 1. Photograph of glass samples under (a) 365 nm UV lamp and (b) fluorescent lamp

Figure 2. (a) excitation spectrum of xBaF-C glass; (b) Fluorescence spectra of xBaF-C and 40 BaF-A glass.

Figure 3.Electron paramagnetic resonance spectra for 40 BaF-C and 40 BaF-A samples

Figure 4. B1s XPS patterns of (a) 40 BaF-C and (b) 40 BaF-A samples

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